1. A. KÖNIG. Physiologische Optik. Handbuch der Experimentalphysik. Herausgeg. v. W. Wien und F. Harms. Band 20, Teil 1. Akademische Verlagsgesellschaft. Leipzig. 1929, Pp. 241. A. König. Physiological Optics.

2. DOROTHY ADAMS. Dark Adaptation. (A Review of Literature). Medical Research Council; Reports of the Committee upon the Physiology of Vision. H. M. Stationery Office. London, 1929, Pp. 138. D. Adams. Dark Adaptation.

In 1929 several new books on physiological optics appeared, of which we shall note here A. König’s Physiological Optics and D. Adams’s review of the literature on dark adaptation.

1. A. König, successor to the late Prof. Pulfrich at C. Zeiss in Jena, has given, in 240 pages, a systematic survey of the principal experimental works in the field of physiological optics, right up to the most recent time. This task is very difficult, since the book is intended for physicists and does not presuppose prior acquaintance with the foundations of the science named; these are therefore set forth alongside the new works. An idea of the book’s contents may be obtained simply from a listing of the titles of some of its chapters.

Chapter 2 gives the necessary information from the anatomy, physiology, and dioptrics of the eye; Chapter 3, entitled “The Doctrine of Colors,” is devoted to the basic facts of color mixing and to normal and anomalous color systems. The phenomena of peripheral and color vision and the dual theory of vision are considered in Chapter 4; Chapter 5 is devoted to absolute and difference thresholds. Here the Weber–Fechner law and the sensitivity of the eye to changes in chromaticity and saturation are considered. The sixth chapter is devoted to the phenomena of simultaneous contrast, color transformations, and the phenomenon of irradiation. The action of brief and periodic stimuli is analyzed in Chapter 7; the phenomena of positive and negative afterimages—in Chapter 8. Chapter 9 is devoted to theories of color vision, with only the theories of Young–Helmholtz and Hering and the Kries and Müller zone theory considered in detail. Of practical interest for physicists is Chapter 10, devoted to various methods of heterochromatic photo*

metry, and Chapter 11 concerns the measurement of colors (colorimetry). The question of visual acuity is analyzed in Chapter 12. The following chapters are devoted to visual perceptions of spatial relations, motion, and depth, and, finally, Chapter 17 analyzes the important and interesting question of the interaction of the two retinas.

Among the merits of the book should be counted the fact that the author has made broad use of the latest American, English, and French literature. The works of Sherrington, McDougall, Allen, Piéron, and others are expounded by him in sufficient detail, although in some cases (with respect to Allen, for example) without a sufficiently critical attitude.

The book is not free of certain errors; here we shall point out only a few that are conspicuous. The curve for the sensitivity of the eye to changes in chromaticity on p. 111 was obtained by O. Steindler experimentally, and not theoretically, as König asserts. On p. 106 three curves are presented, called by the author’s namesake, the well-known Prof. A. König, curves of “elementary sensations,” as distinct from curves of “fundamental sensations,” in which phenomena of color blindness are taken into account. The author erroneously calls these curves curves of “fundamental sensations,” although in the colorimetry report of the Optical Society of America, from which he borrowed these curves, it is clearly stated that they are not equivalent to curves of “fundamental sensations.” The Weber–Fechner law is given (p. 65) in an incorrect formulation, taken by the author, apparently, from Høttinger, etc.

Despite all these shortcomings, König’s book can be recommended to physicists for initial orientation in the colossal literature pertaining to this field.

1. The small book by D. Adams gives an exhaustive survey of all the literature on adaptation of the eye and the phenomena connected with it. It is considerably broader than its title and considers, in essence, all those functions of our vision which in one way or another change depending on the adaptation of the eye.

Appended to the book is an enormous and well-compiled index of the literature, occupying 23 pages. Among the merits of the book should be counted the fact that the author has included many (20) different tables with numerical data borrowed from the works reviewed. For the compilation of these tables the author will be appreciated by everyone working in the field of physiological optics.

N. Fedorov